Storage tanks are used to contain and store a variety of materials, including water, gasoline, oil, etc. Storage tanks are commonly buried under ground for aesthetic and safety reasons. The first step in the installation of a storage tank is to choose an appropriate site. The ground is excavated to accommodate the dimensions of the tank and to meet various regulations regarding the burial of the tank. Usually, a chain or a metal strap is placed under each end of the tank. The straps are then connected to a crane or other piece of equipment capable of lifting the tank. The tank is placed into the hole and the metal bands are removed from beneath the tank.
Eventually, the tank will have to be removed from the ground. Environmental factors take their toll on buried objects. Over time, the integrity of the storage tanks are compromised and their contents leak out, necessitating the removal of the tank. Remodeling or a change in requirements may also precipitate the removal of a buried tank.
The extraction of storage tanks from the ground can be a lengthy and expensive process. First, the tank is usually drained. Next, the ground around the tank is completely excavated. This is usually a tedious and/or dangerous process if there is a high water table, flooding or if hazardous materials have leaked into the ground. A worker must thread a chain or a metal band under each end of the tank. The chains or bands are then connected to a crane or a backhoe equipped with lifting hooks. Care must be taken in order to ensure that the tank is substantially centered between the metal bands, otherwise, the tank will tilt and only one end of the tank will be lifted out of the ground. Consequently, the metal bands will slide off of the tank. It would be difficult to slip the chains under the tank again since the tank may no longer be in a substantially horizontal position.
Some storage tanks have a manway located on the top of the tank which allows a person to access the interior of the tank. In this style of tank, an alternative method may be used to lift the tank. A loop is formed at the end of a cable or chain. This is done by bolting or clamping the end of a cable or chain onto itself as shown in FIG. 1. A worker must climb down into the tank. The loop is lowered into the manway or into another access port. The person inside the tank must insert a curb pin through the loop. A crane is attached to the free end of the chain for lifting the tank. The person inside the tank may have to hold the curb pin until the slack in the cable is taken up, i.e., until the curb pin is raised high enough to engage the tank wall and is properly oriented. In this manner, the weight of the tank prevents the curb pin from slipping out of the loop.
A loop and curb pin combination may similarly be used to lift sections of a piping system. Many piping systems include predetermined lengths of pipe and various fittings (manhole, meter, valve, access, etc.) The use of a loop/curb pin in a fitting having an access port is similar to its use in a tank. In order to lift sections of pipe, a drill is used to cut an appropriate hole into the pipe to accommodate the loop/curb pin. In addition, an apparatus known as a pipe hook is also used to lift pipe (see FIG. 2). Two pipe hooks are usually required to lift the pipe; one at each end of the pipe. Consequently, two people, one at each hook, are usually needed to steady the pipe hooks until the crane takes up the slack in the cable.
The above methods require access to the interior of the tank or pipe. Further, they are labor intensive. Accordingly, previous methods of lifting tanks and pipes are expensive and dangerous. Injuries to fingers are not uncommon since the curb pin or pipe hook must be held in place by hand in order to attain the proper orientation. Also, the cost of providing protective gear for employees who must climb into a tank which previously held hazardous materials can be quite high.